Back side illumination (“BSI”) CMOS image sensors (“CISs”) are becoming increasingly popular due to improved performance relative to conventional front side illumination (“FSI”) CIS devices. Even though BSI devices eliminate the problems caused by multiple levels of metal interconnects in the light path between a lens and a photo-diode region of a CIS, BSI devices introduce their own types of performance degrading features. One such feature is color filter uniformity induced by topography at pixel array boundaries. This topography includes so-called steps between back-side metal features and the pixel regions.